The present invention concerns a steering spindle arrangement for a vehicle.
As a rule, a steering spindle arrangement for a steerable wheel in a vehicle comprises a steeling spindle bolt with a conically shaped part for securing an axle beam. A stub axle that supports the wheel is pivotably arranged on the steering spindle bolt by means of an upper bearing, which can be a conical roller bearing, and a lower bearing, which can be a sliding bearing. In this case the upper bearing absorbs both axial and radial forces, while the lower bearing absorbs radial forces. However, most roller bearings need to be pre-tensioned in order to eliminate play in the roller bearing. One known means of pre-tensioning the bearing is to use shims. The inner ring and outer ring of the roller bearing can be loaded by means of appropriately placed shims with a force so that the bearing play is eliminated. However, the installation of shims is complicated and does not always produce the desired effect.
WO 97/13674 describes a spindle bolt that is threaded at both an upper end and a lower end. An upper nut is secured on the upper thread and a lower nut is secured on the lower thread. An inner ring on an upper conical roller bearing can be locked against a surface of the axle beam by means of the upper nut. The upper conical roller bearing and a lower conical roller bearing can be pre-tensioned by means of the lower nut. In this case no shims are used to pre-tension the roller bearings. Because the lower nut is used to pre-tension both the lower roller bearing and the upper roller bearing, forces are transferred from the nut to both a lower arm and an upper arm by a bearing journal. This force loading of the arms of the bearing journal results in elastic deformation of the bearing journal. Pre-tensioning a roller bearing by means of an elastically deformed component is not desirable. Roller bearings should be secured and pre-tensioned between two essentially rigid surfaces.
It is suitable for a vehicle wheel that is arranged on a pivotable stub axle to rotate around a spindle bolt with a suitable rotational resistance. If the rotational resistance is too low, there is a risk that vibrations will arise in the motion-transferring transmission that transfers steering motions from the vehicle steering wheel to the steerable wheels. If the rotational resistance is too great, an unnecessarily heavy force is needed to turn the wheels.